弯扭作用对连续梁桥顶升的影响

Influence of Bending Torsion on Jacking of Continuous Girder Bridge

摘要:

连续梁结构具有重量大、刚度高的特点，对顶升改造具有较高要求，顶升过程中易产生位移不同步引起的结构弯扭，进而产生内力重分布，严重时将导致梁体开裂。以浙北地区某连续梁桥顶升作为案例，对该桥整体顶升过程中产生的裂缝进行成因、位置等具体分析，指出连续梁桥顶升应着重关注位移不同步引起的扭转变形，建议采用位移结合支反力双指标监控措施，防止顶升期间支点位移不同步引起的弯扭作用导致梁体开裂。

Abstract:

The continuous girder structure has the characteristics of large weight and high stiffness, which has high requirements for jacking reconstruction. In the process of jacking, it is easy to produce the structural bending torsion caused by displacement asynchrony, and then the internal force is redistributed, which will lead to girder cracking if seriously. Taking the jacking of a continuous girder bridge in the northern of Zhejiang as an example, the causes and locations of the cracks produced in the whole jacking process of this bridge are analyzed in detail. It is pointed out that the jacking of the continuous girder bridge should focus on the torsional deformation caused by the displacement asynchrony. It is suggested that the double-index monitoring measures of displacement and bearing reaction force are taken to prevent the bending torsion caused by the displacement asynchrony of bearing point and the girder cracking during jacking.